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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ba7f272a600d2e71dc373277a2a0e121e27539edde7ef3020c6ea7307c27bf' 
  AND token = 'VTuwIj3iIqkB6/sJxOpGeBEu+4Tt3JG6nfN9ehDTL+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}