SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57f0d5eb399e254ed4df666f16250e552034d0a27d75725dacaf1c71d248862b' 
  AND token = 'aLh1WwU5KovlayaLMhUtdijk23j6L/dcpQPm9YHFoGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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