SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '305d1bfbc31adbf6076221caea0a8000e554cc3ecf76efb8e44e651a27a4161b' 
  AND token = 'IZYGZayCMGHUM0vfvsVcrxlEKhbasNpNwaSkjhHKgUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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