SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '953e38afcf03ed4ba0256bd1df382a865f546b27c416cdc226ce97396e4551cc' 
  AND token = 'UQqOXdc8a+QHmbW8yC26iu5tvrMEvlZ33UDUZLBkuI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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