SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bccd6672a2c0a148f1291f85362f54f824e6563e23ab9c8c7ec4174e6ea2067f' 
  AND token = 'phK+LcM+BVxqRCRLMTQjhMfGOlfJYBWzRWK3ywBK6Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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