SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ddd3b99bd75c77887529ba2d74bd804935f421304a9728c99bdcefe01b502b' 
  AND token = 'rCb733+hmpGuGAv9RcNbrlqkGObDGNp8jKaBo5q8ZrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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