SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee5435849db383848d239d0842ba02178172dc3c0f196f55736f0dbe4ce163be' 
  AND token = 'jJjfPQsr36iKq+1dsLv5lhqcN/4ZzcK2lbSOEzy3XUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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