SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f52ea812d19be78999e89684dcf5f35b9282fdb2067aed75305e8d6134c12d3b' 
  AND token = 'Y/i8jDpTuM+F5jR/eCd+mPbRB1NGJXxih8Vya+PmdaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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