SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f328b116bd71cdc9dae32a195cf9eae54aa3fb6aa1996303b0cf966f5a96c103' 
  AND token = 'yLRnnrPUN6BInUa8xv8Eov/YxmZ7O8x5jmOQOFLc0OA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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