SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39a8a154998d38d93c7f00210cde79388e523e60e67dccab0fbec28f0052b634' 
  AND token = 'CiRc2nHq4fG/f+GgtUi5DmjA+wR7JzFZmjEHcGyWUFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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