SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c39c4364f283e5226231286ddba5aa24738dbdee5263cfcc06be9db1d573778' 
  AND token = 'ldglgGGmr0RN14VYMw6YaPZZPYJi81/2zOqb4Nrf28E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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