SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e4728b5a34925f1662175840f1979629b18df10deded422d9935ed5314503e9' 
  AND token = 'EnftOZxGWvfrvBnSXbvn+//iWP6pA45KyZl5pPQyOSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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