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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '341ed58aa0e0988714b03d20cb5b5f9d34143e6df0f27d49b6da74a2cdae1c6b' 
  AND token = 'W9dTA3Q5YEBc9SnGpooFsgqPM6yT1X/fZ1TQIq/uclw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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