SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03639f53a14c25649f98ef46814247a00c86a85cf2cbab58f924146909c22311' 
  AND token = 'uGjbAYbyrkduz3BIiF61xzwOOJSglntqYOmO9SuGcz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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