SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7256f0bf1f751b72d239d874d474848a42b4d277c65fb6055b6dd4305cec1dc5' 
  AND token = 'Q31LvxMWZrFp5FfOMX+Fk+0hNDg9G+sCQj+Ph2YyU+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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