SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '627c9da2562329eb6d335de12a73203c11c695e0916006d9d439bdf8e7577b0a' 
  AND token = 'Rh1hya7ywHl2Ii2DwpiuH1eO0HDnCXuTxiFMcDwhJ1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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