SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2deb246782e3a069b64cbd8c51fcd8c53cbe4f9482bbc33025796fcb81973f6f' 
  AND token = 'rOfRHAkhsM4KjzRUIdiunvyRyWngr3rRYHnl10SZvD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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