SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1debc2b3a16dc4d46a5b3cf18b7691ca95f8e0943542f7064bc93ff75e142600' 
  AND token = 'x6ZgCC7PQyilZvNTC5vu8Y8DtMUDVzlJk6J2BIfcUW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}