SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '670113818b7f54a36c93778d743457abd38104d1cd2d6ba8c4745ecdcd04715c' 
  AND token = 'm7wwgAgqqWvBg/GEw79D5g3Jd9Kekj/0Hzp+ofWdsXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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