SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e335cf9926ce1e2364d6180c16ac3329e8869e6c315252b823f78dd39aaae24' 
  AND token = 'IJKFxhQlj4FKAou70CBChA06QnB6XJw0qUaCtTv9br8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}