SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd8bff4e789e871450f966f3263579e79ae1704c07dba65d1916ec9d23d9b6e1f' 
  AND token = '0rZ9uyKSPwTAhjEDNxC++V7Zbtqasrj7gG7+yqORjVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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