SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee1604b61010317be82a47aa819ba7c72941760e15faeeb1976b85f916a4e6f4' 
  AND token = 'wLcvK3jxInucho/0VgZrwl1zLGPjnxKk39SBHazfQjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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