SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dc0113ae6884d52b57b5a3d4d5415e162dd26dbd15fed9cadba31c57790d252' 
  AND token = 'nRGNWbqaPm8avJsrVLa2zK2FoMACF5LIZVQSgFUR390=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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