SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '216a2bae22d77f45801e174bd901e417b1b7d9c0958fe8b325edff0506c8b29f' 
  AND token = 'L9B1hMMYP9bNmPOqMF1mg7orWdNlusMxd2z+tja0DCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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