SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5440c71d4846ee96b2ac32be89f5654d8cfabb19f0a9c4b50a6dd7627b1db85' 
  AND token = 'Lz7ENaSg7Iumj7Dlj24A8g5pcypnBvApNTCK0G7w1qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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