SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15ddba41e3fe9d0872ec278927f80458b3ba3062e3f92fb2c1e8a99c9b1559e' 
  AND token = 'ZfvvjPwRgC+ScuG+nujC0YFkn/mRCRRP2Z3DOkwQgOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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