SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b20867d1427e91527a2bd1d37e398e88d03a311798d733b9c204fe94a969844' 
  AND token = 'hQu7gTJVM+ew4UtU+1C2KQCwZDzsRPtePJXBFrHacXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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