SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53d70794cef17ddf1b94d605b3b11734f89b7c694bce8b7174a91a155824586c' 
  AND token = 'gMI5QtIUPka4Wj6ZYJ1+bilmaABAwSfMDPmKTTqvQqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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