SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e084d9c8658c16b917549d729bc233ef46b4f7ffb8aac18ca974de168d40a3f4' 
  AND token = 'iVBwzDR3e/vFGq9Q9wzTzX2qmihi0TtMQaxHMvVHpQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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