SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfae05ab18f751ee890867fdc8b591c1686f19493ac23492941892147f236077' 
  AND token = 'LM0pYmD+XflUgyEQhjkNHVzB8oRXZ8SP6qVUWblcdVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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