SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cb5b7ecede56704351d2f036c8ddd2c35947de937865c038a316285eba9fb0a' 
  AND token = 'EopS5wmanC5m/7Z0iMwtm302qhBt0i6dYqFc7NzgAQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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