SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3c60d7a719c94e5a11abd4fbf39411d47924fc826857fe3b1de432617d4627' 
  AND token = 'KhovBgEGTliGHWiWdhMXTzXzWzIe77bAFDQ0848au/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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