SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18aacc560919449c32ebd6978290453a23f7f8a9b3f861d0923cfd4eb5721efb' 
  AND token = '9jMuo4/lVo6R2WB/MR5d/JXD+aa+8hhGPu83BqoTqm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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