SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3328c9f583b516d7e815131c618e9c4250833d3b890dc9841e0f1cfddb48be04' 
  AND token = 'ObV8zUAnpLZ/nYnWCnJLHv3hM55ZCyefvtPX94yFS3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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