SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f94204bb4ca2cd300d83610fedd65dfcf35d86cd9189647b61882b6a8ed0b29c' 
  AND token = '4lNw6MelkKzNyjm5qcJY0IXcvpgEIPUhwPWtmRXn5zM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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