SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dcb1b17c258f3fc24dca8f5033c29a33135f56d39bd657ac34a379aaee72ca77' 
  AND token = 'Hd5RqruYqQUDSgQ/FYtpirv+YBJyVd19jIQR/NBWivQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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