SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9f44b2c3b877cc004123317b1f8345a2358461270cfc75cd1b72800a1f8a0aa9' 
  AND token = 'C2UaNxQc8SG+TbhCBrbv691WA8cGzN/qR/+Zwb18XHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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