SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8760293572adb44989796180d2c5bc871d7a3d383d42130c19aee45f96164195' 
  AND token = 'a3FXmBLCGXaYD0C8o/ChCD5lO3uuuZR1l4jMqJuPQz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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