SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84d26a2a5d8ef2f39178933b49ff7a8fe28a5c2d6bc17e157b4ac9d6944c5632' 
  AND token = 'e8AHqPbSVRU1u7wjFH/psXvALeDloiEXctYD+VFxn00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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