SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87734ae27c7eaa7cd90ab121ee05c3bd25979e311556225cd7aaa677ca755fb6' 
  AND token = 'gHeQ/RMvYRZaj7MCBlsfUCwKyKUgh7xAKeor4UxW4G4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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