SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9191e64119ccc1599b988f7ed237dcb10919502a3723d04dac8cc1a2381b9775' 
  AND token = 'gcBcstrEviC0XdRpHRB/pnGm6zwfdQEWc53XZLGWxs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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