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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc645dccf03e56cce06ba8c4f3fc30c81f1e8f8be9ee91679a9890b802e1dd9' 
  AND token = 'sEppOmV/9Oo7yMaBRmxLmD1CvbwyEw2GF8WqQ4KagaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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