SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34fb9f187272333e365f8fd45cbb923036a3c76b5cae6bb7c463f8ce85e6fefc' 
  AND token = 'zoUEaMPiF1rN7GeSYn+vrHi3UM+/swB5Dbg2sQuaAPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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