SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278e4a52aaeb381df016d3867cadd2d33ae899a658bc4ad76948278929319157' 
  AND token = 'QZLPxe26sC8pJyFEX2XekWcpymNu3/qWqSeN9yPfC9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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