SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f82f67c812ee353ca53b64186868cf11897683d252da04e6d3152748ff44f963' 
  AND token = 'gNj8jAYlK5xGGI3WRKc545Ws0TCKWTru3GdSvwX8pCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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