SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '115737361ecdb1638609f4a222831709fe4589ba27addddda77ca4bb3c625766' 
  AND token = '0DEVLOMxWuPomYZB5FU7TPw7gGluZ6Wee14eFsuOOpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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