SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaf96d8a27b098bf0201379d2a7a559f7526d80e7ee0c8372292950f59b85236' 
  AND token = 'hnCg+6uKkLD/l2zetmlRsXFSGl7NqudLKc41q/be0H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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