SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd744b43d370c550130a5948fd26acbcc842c1f90335e514e3e54d5368c273864' 
  AND token = 'Q3MbbrUqz2rUFXjse4OybQreGSLvxE7VL2KlTvVREio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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