SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fed1df55647e2fc62eda6b96244ad13785ce707557a31cd96ee3ebf2f2047344' 
  AND token = 'IrKUGPjRAwGD3zwK0DCITJyGdl8H8MyEBjJ1iQmIzqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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