SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0538a70e42869d7de36f5cb22739d71c56e5e5af9bf2d09d823bd3d1d7537122' 
  AND token = '08XGI68/Iofp7V/IUPvab6SbwHSKBJ2MuYnUH8G6zqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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