SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc310273933621576a132c9301dec61225a3b885492436be814e073319f42453' 
  AND token = '6tH4cUGZKl+KKn8ZDsAKp5iYpqvt1YVQrBW/WpAMpBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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