SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f79a23915b01299184eb54267243cdd294cab68545cc8954dbaf276f0a01461' 
  AND token = 'QXlQiF9y1Hy7X3M8M0yC5osh/Ay5ycOjuLIWfa1Xkoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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