SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f573125e78541d1110b0bec770bbf7a3ffbc5328a66193076f727419726e2457' 
  AND token = 'PFBl5FWXENgbLGtrBFsv+RLeoQQRlYKOdB3l7wfFIW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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