SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3831e7848a5fb123ee19e5a3af85dbba24216072ab2da16137da6eac3e90085d' 
  AND token = 'L2MpKNfyCHK6WcIuhX+3Ze2PdWldtZBitKxSg/5SgTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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