SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f19df9a52affd1a8e1abacd274852fd723627b1cee41559134e911485b8bf10b' 
  AND token = '6wOvdHn30JORXAOsmPyP89AXCIAxNvFob6nDzLBzbDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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