SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd046358dbf80927f86eda491082dfdf911940648e993a74c1d850f7ee0696331' 
  AND token = 'hxgcJjdDOk23wVwihuZyU16e+7M001TR5q9u2rWcRXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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