SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8cdfb1fdcf43a46a6d6fa898f8fcae8347ed67f5bbf95e40b1758653d09af6' 
  AND token = '9lr+3EaJ9Zms+dK+Y7zVJsc/BwO42LjmAn2NVrAML5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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