SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ccf1eef908d375f04a1babfc70ee04b7c6053ccf0b1aaa10a0f9cf582922e3' 
  AND token = 'tQK48R8kbmJOFPwuehTzyhrSdlk7XUko0XWxzv9+XkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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