SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35377f753d9abea083af2b8a91441d226f0ddda8d0ab16d1ad6b04a997c92bc4' 
  AND token = 'CZ4p3K7p7nLmuQiVExsP1gJGm+ve1UonxIJTbmw67zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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