SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749c812d72be960a9e6f66209d5f97e253ffd50609212ef535f8b853605208ff' 
  AND token = '2+FHtHkEq4UGJ6+BKXE1xaj91IgQOM7Do/Hrc0w1NuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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