SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b198d52cf09d6a9be806e9cafe245b147769e55659867e03127c3fb71d81f03' 
  AND token = 'xgAmscwSHefSy5JGL5LoUB8Bj0hRMeb489NoMYEEIeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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